Amine groups-functionalized alcohol-soluble polyfluorene derivatives: Synthesis, photophysical properties, and self-assembly behaviors

A polyfluorene derivative with primary amine groups on side chains, poly(9,9-bis(6′-aminohexyl)fluorene) (PF-NH2), was prepared through de-protection of its analogue polymer poly(9,9-bis(6′-butoxylcarbonylaminohexyl)fluorene) (PF-BOC) with hydrochloric acid followed by neutralizing the salt form of poly(6,6′-(9H-fluorene-9,9-diyl)dihexan-1-aminium chloride) (PF-NION). PF-NION had good solubility in methanol, DMSO, and DMF. Scanning electron microscopic images of PF-NH2 in thin films revealed that intramolecular/intermolecular hydrogen bonding and π–π stacking interactions probably played an important role in the formation of special surface morphologies, which might be beneficial to the molecular ordering and device fabrication. The electroluminescence property of PF-NION was recorded on a simple polymer light-emitting diode (PLED) device configuration of ITO/PEDOT/Polymer/Al. Pure blue electroluminescence is achieved from double-layer PLEDs based on PF-NION as the active material with the CIE of (0.16, 0.08).